1. Field of the Invention
The present invention relates to a displacement transducer. In more detail, the present invention relates to a device that can amplify or reduce displacement, using Pascal's principle.
2. Description of the Related Art
Piezoelectric elements and super magnetostrictors exist as elements capable of high-speed response in the kHz operational frequency range. These elements have a high-speed response, but there is a problem in that the range of movement (stroke) is minute, in the micrometer range.
A method for magnifying displacement up to a practically sufficient level by amplifying displacement using a mechanical “lever” has been considered when using such an element as an actuator.
However, if a high-speed operation element is combined with a mechanical displacement amplification mechanism, response speed of the system overall is commonly slowed to around 0.01 seconds due to the mechanical resonance characteristic of the amplification mechanism, which is a major restraining factor on the design.
A displacement amplification mechanism that uses Pascal's principal for fluids has therefore been proposed (refer to patent publication 1, for example). With this displacement amplification mechanism, it is possible to increase amplification factor of displacement as a proportion of surface area s of a driven portion with respect to surface area S of a driving portion (s/S) becomes smaller. However, because of the displacement amplification it is necessary for the relationship s/S<1 to hold in principle. By making s/S greater than 1, displacement attenuation is also possible.
If this type of displacement amplification mechanism is used, it becomes possible to simultaneously satisfy the need for high displacement amplification factor and high-speed response.    Patent publication 1: International Publication WO2003/102636
With a displacement amplification mechanism that uses Pascal's principle, fluid is used as a medium for transmitting displacement of the driving section to the driven section. The fluid generally has a characteristic of large volume fluctuation (expansion or contraction) with temperature change.
With a conventional displacement transducer mechanism, therefore, there is variation in the displacement of the driving surface or the driven surface attributable to volume fluctuation due to temperature change. Specifically, the conventional displacement transducer mechanism suffers from variable displacement due to temperature change, which means that there is a problem of deterioration in the accuracy of the displacement to be transmitted.
The present invention has been conceived in view of this type of situation. An object of the present invention is to utilize Pascal's principle to provide a displacement amplification device that is not susceptible to the effects of temperature variation.